How feasible is a man-portable firearm capable of incapacitating a large dinosaur with twentieth-century technology?

Question

In the movie Jurassic World there is a scene where a specialised military response team engages the Indominus Rex, a genetically modified dinosaur said to be of comparable size to Tyrannosaurus Rex. The weapons they carry are largely typical late twentieth to early-twenty-first century firearms, and even the crew-served weapons - including some kind of machinegun fired from a helicopter, don't seem to do any significant damage to the dinosaur.

This has some precedent, in that even real-world large mammals have proved challenging to dispatch using firearms - the elephant gun was developed specifically for hunting the largest of game.

A realistic dinosaur of the genus mentioned previously would probably weigh somewhere in the region of 15,000kg, whereas the largest African elephant weighs around 6,300kg. This indicates that the movie drastically over-represents the size of a Tyrannosaurus-type dinosaur, which appear in the movie to be the height of a three or four-storey building at least and massing at a rough guess at least ten times their real-world size.

For the sake of the question, let us assume that we are aiming to deal with a movie-type dinosaur - a very large and very durable animal, well in excess of the largest terrestrial species to have been killed with a firearm.

How powerful would a firearm have to be to kill this hypothetical dinosaur with one to three shots placed with skill, and what technological adaptations would be required to make this weapon readily portable in the manner of some kind of small arm? By small arm, I mean a weapon such as a rifle or shotgun, or exotic variations such as gyrojets, with automatic or semi-automatic loading from a magazine, potentially specifically-designed to kill an extremely large animal if this is necessary to achieve the goal. The weapon should be practical to carry and fire on the move by a single operator, including while under attack by the animal. Is such a thing feasible?

Answer 1

Very Feasible

According to this article, you could quite likely do so with a standard assault rifle (7.62mm), with good placement, as the skull of the T-Rex at least, and probably a good many other dinos, is full of holes, and so shots could be fired into the creature's brain without having to contend with bone.

Alternatively, something beefier, such as a .50 cal or 20mm (or smaller, high grain count ammunition) could rip through flesh and bone for days, very likely passing through a dinosaur skull with little effort, assuming your aim was less than perfect (and with the recoil of such a round, that's a reasonable assumption, if not properly braced).

Point being, firearm technology has advanced considerably since the introduction of the elephant gun - most notably the switch from black powder to higher energy smokeless powders - and with the use of specialty rounds, such as armor piercing (for access to organs far from the surface) or dum-dum (expanding) rounds (for arteries or organs near the surface), you could probably do it with a hand gun if your aim was true (through the eyes, nostril cavity, soft palette, or carotid artery) and depending on skin thickness. Quite probably, with a 10-12 round clip of armor piercing rounds, you could probably reasonably rely on enough internal organ damage to kill it with only body shots, though this might be too slow to prevent it from taking you with it...

Answer 2

Any man-portable anti-tank weapon from the mid-twentieth-century onwards should be capable of dealing with a dinosaur of any size. I think you'd want a high-explosive charge on it rather than an anti-armor head in order to do the most damage to what is, despite its size, a soft target.

Happy bazooka-ing! :-)

Answer 3

Go hunting with the appropriate weapon type and tactics

Dinosaurs are equivalent to lightly armoured vehicles (albeit very large ones) in terms of durability. So the best tactic is to use the same weapons that have been developed for that purpose today with the associated tactics.

Tactics are the first consideration. When hunting armour, an outright kill with the first shot is desirable, but immobilising the target (a "mobility kill") is almost as valuable. With dinosaurs that have no ability to shoot back, a mobility kill is even more desirable. Mobility kills are also much easier to achieve for those lacking detailed knowledge of dinosaur physiology - faced with a dinosaur I would have no idea where the heart(s?) or brain (s?) are located, but the spine and joints are pretty obvious and could be damaged by light anti-armour weapons.

Regarding the weapon choices - my suggestion would be to go with 40mm grenades as an easily man-portable option with a relatively high effective rate of fire. The M430A1 HEDP round can penetrate 76mm of steel plate, which should be ample to penetrate the skin and shatter bones for most dinosaurs. The grenades can either be launched from under-barrel grenade launchers (if the troops also need standard rifles to deal with small dinosaurs) or from the Milkor MGL, which is a six-shooter. One or two shots to a leg to immobilise the target, then a carefully aimed shot to the spine and the target will die.

For those who want something heavier with a longer range, go with the Carl Gustav 84mm. The FFV551 can penetrate up to 400 mm of RHA, so even the toughest dinosaur will have a large hole blown through it, wherever is hit. It can target stationary targets out to 700m and moving targets to 400m (some ammunition types can go out to 1000m), so this is the weapon of choice if long sight lines are available. However, the weapon and ammunition are much heavier and the back blast danger area is significant, so this is ideally used by sniper teams in fixed positions rather than for patrolling.

Answer 4

The answer was already given in Jurassic Park

The Lindstradt Gun loaded with cone snail venom.

Whilst this particular gun is fictional, the snail venom is very real. A dart gun could easily be loaded with this venom.

Answer 5

Standard 5.56 or 7.62 caliber rifles would of course not be effective against a large dinosaur, unless the eyes are successfully targeted.

5.56 or 7.62 caliber machine guns, while not immediately lethal, would be quite annoying, and after a big enough number of hits, our dinosaur should bleed to death.

0.5 BMG (12.7mm) machine gun should have enough power to penetrate internal organs, and with some luck, drop the dinosaur within several seconds of firing. But this caliber is still insufficient for a quick and reliable kill.

0.5 BMG sniper rifle probably can kill the dinosaur in a few shots, but this is again won't be a reliable kill.

Shoulder-fired anti tank missile have the greatest chances of killing a large dinosaur in one shot. The wounds would be deep and extensive, and even if vital organs are missed, one wound would likely be incapacitating. However, due to cauterizing, bleeding would be relatively low.

Answer 6

As others have said. You'd choose weapons that were effective. Very high energy 'dumdum' style rounds would cause quick incapacitating damage. Aim for the legs. If you could guarantee a headshot.. a single 50 cal dumdum sniper round would pretty much remove the head of any dinosaur. If you were being chased.. had one shot and absolutely must stop the beast.. an RPG with a shaped charge aimed at the torso would work. Or a minigun and a lot of swearing.

Answer 7

Many people have mentioned things like .50 cal sniper rifles, like the Barrett Light 50. This will allow you to engage from extreme distances (Canadian snipers have scored kills from distances as great as 2.5km and the absolute world record is an astounding 3,540m). While it is questionable just how much energy the bullet will have at that distance (enough to kill a human being, certainly, but a dinosaur?) it indicates you can find a proper hide and engage at such great distances that the dinosaur will never become a threat to the shooter.

This suggests that "anti material" rifles firing even larger rounds (some have the ability to fire 25mm cannon shells) will be suitable, since there will be a high amount of kinetic energy and the ability to add an explosive charge to the shell and create a lot of terminal damage. The dinosaur will have a large, crippling injury and bleed out quickly thereafter.

Barrett XM109, which fires a 25mm cannon shell

Of course, at this point you are starting to stretch the definition of "man portable". Only very large and well conditioned people will be capable of using these weapons effectively, and the huge recoil force means the only feasible way to use them is in the prone position.

One way to get around this limitation is to switch from rifles to grenade launchers. A 40mm low velocity grenade from an M-203 or similar weapon has an effective range of 400m, which is likely enough to deal with most dinosaurs, and the force of the explosion and the shrapnel from the round will provide the killing mechanism. Most people recognize the M-203 in its underslung configuration on a rifle, but kits can be purchased to make the grenade launcher a stand alone weapon.

M-203 attached to an M-4 carbine

M-203 in a stand alone configuration

Finally, hand held anti tank weapons offer the ability to kill virtually any sort of dinosaur you encounter. The primary issues with these sorts of weapons comes form the fact they are unguided, so missing is quite possible, and the fusing is generally designed to detonate the warhead on impact with an armoured surface. The AT-4 or RPG warhead might penetrate the dinosaur but not detonate, which is a problem for you. Using a thermobaric warhead like a Russian RPO-A Shmel provides an almost guaranteed kill (both due to the intense heat of the warhead and the fact it will suck out most of the oxygen in the area for the short time it burns), although you might have some issues with the fact the surrounding bush/forest/grasslands will also be burning intensely after the warhead detonates.

RPO-A Shmel

So people with access to modern weapons will have little difficulty dealing with dinosaurs (assuming they are properly trained to deploy and use these weapons, of course). Perhaps the biggest issue is understanding that while dinosaur megafauna are the most impressive and well known form of dinosaur, there are plenty of very small and equally dangerous dinosaurs around. The way to deal with the multiplicity of threats is likely the M-4/M-203 rifle/grenade launcher combination.

Happy hunting

Answer 8

Anatomically this depends a lot on the species, but for most dinosaurs the weak point on is the knee. The knee (and legs in general) is supporting most to all the weight depending on the species, It is supported mostly by soft tissue and lacks the large interlocking system of mammals knees because they have to be able to twist to make up for the hips. They are also one of the few vulnerable portions visible from the front, an important consideration. from the front don't bother with a head shot, your chances of reaching anything vital are very slim, the brain is tiny and behind multiple feet of tissue and bone, even from the side it is a small well protected target.

In real animals injuring an animals is usually enough to drive it off, but for super persistant movie predators we need actual debilitating shots. The most reliable kill is a gut shot but not the easiest from the front. Unlike mammals lung shots don't work (at least in the saurischian dinosaurs) unlike mammals their lungs do not rely on negative pressure cavity they are also smaller targets than similar sized mammals. A heart shot is your best bet for an instant kill but it is not an easy shot from the front although there are fairly good visual markers form the side (just shoot behind the shoulder joint).

As for weapons you will need high penetrating power but any high power rifle will work, you are punching through bone and scales and a lot of tissue to reach anything vital. In the most heavily armored dinosaurs something with a bit more penetrating power is needed, unless you are shooting from the side, you may have glancing problems but even then just upping caliber or to armor piercing is enough. You can scale this to however abnormally thought your fantasy monsters are.

Of course this assumes you are targeting large dinosaurs, for smaller dinosaurs just match real life birds of the same size, although as the australian government found out large birds are not as easy to kill as you might think.

For the largest sauropods you need just need to shoot for the legs with any anti-material weapon, the leg bones are massive but they are still bone, treat like the equivalent size wood log for penetration. Alternatively go with full auto high power rifle rounds and just go for massive trauma of the torso, blood loss is blood loss. Don't bother shooting for the head, it is a small swaying target often high off the ground.

Of course you can forget everything here and just use explosives ordnance, massive trauma is massive trauma.

Answer 9

If taking a few minutes to kill a T.Rex is acceptable, then use a sniper rifle on its head, as others have said. If you need to kill it fast then you need a substantial internal explosion. This will shred enough of its organs to drop blood pressure to zero, incapacitating it in a few seconds, and with a little luck, you'll blow a leg off, immobilising it.

So the trick is to get a substantial explosive change in through a few feet of bone and muscle and then set it off. We don't build weapons to do that now, but there's nothing impossible about it. The basic method would be a variation on a tandem-charge warhead. These were invented to combat reactive armour, and have two charges that detonate separately. The first is intended to wreck the reactive layer of the armour, and the second to penetrate the underlying passive armour.

An anti-dinosaur warhead would start with a shaped charge, which is intended to blast a hole deep into the T.Rex. It would then fire a non-shaped fragmentation bomb into that hole, intended to detonate in the belly of the beast, wrecking it with blast and shredding meat with fragments of metal.

The weapon you'd use to launch such a warhead could be a rocket-propelled grenade launcher, like an RPG-7, or a one-shot recoilless gun like the AT4. Both are readily man-portable. Anti-tank guided missiles could be fitted with such warheads for use at longer ranges.

Answer 10

The Javelin

No, not the African weapon, unless you count Wakanda. The FGM-148 Javelin of Whiskey Tango Foxtrot fame. 30 second to warm up the refrigeration unit, select either top-down or sideward attack, then you use the thermal sensor on the launcher to acquire the target. It powers up the thermal sensor on the missile to match up, and now the missile knows what target it wants. You're walking away like Iron Man while the Javelin finds its own way to the target.

It's a 2-stage HEAT warhead, a hypersonic stream of liquid metal. A weak first stage drills through explosive reactive armor (ERA) just in case the dinosaur has any of that, then the larger second charge punches through the meat.

Polish lances

At the beginning of World War II, the Polish were famous for charging German tank brigades with horse cavalry and lances. And by "lances" I mean the Wz. 35 anti-tank rifle. It shoots a plain slug with plenty of energy. It didnt aim to penetrate (a penetrator would go right through a dinosaur leaving a bullet sizd hole, probably not fatal). This was meant to flatten against the plate armor, efficiently transferring its kinetic energy through the tank's armor, causing sections of metal on the inside to spallate and hit crew. An ingenius design and a well kept secret up until making its introduction to the Germans. The horses were simply for mobility. Anyway, against dinosaur hide, it would flatten, deform or tumble, doing hollowpoint-type damage.

Answer 11

I give you the M-38 Davy Crockett. At 38kg its slightly stretching the term MANPAD - normally a crew of two people is used to carry it. For those unfamiliar with US military hardware, it is a recoilless nuclear warheaded weapon, with a throw distance of 2km, lethal range of 500m, and a yield of 20 tonnes of TNT. That should stop any dino quite efficiently.

Answer 12

Extremely, and you don't need to go to a Barrett .50 BMG to do it.

W.D.M. "Kilimanjaro" Bell was known for lots of things, including killing lots of elephants. He prefered the 6.5x55 Swedish Mauser round, a 160gr steel jacketed bullet moving at about 2600fps muzzle velocity. Granted, he specialized in this, and spent plenty of time developing the perfect shot placement (from behind, at an angle, into just behind the ear).

Plenty of larger and more powerful rounds available today, in packages that weigh under 10lbs with a nice scope, and they can be capable of putting 3 shots into a 1" circle (or less) at 100 yards.

All comes down to shot placement (in a hunting situation).

Now, for defense, I'd be looking into one of the very high capacity 12 gauge shotguns loaded with appropriate slugs, a souped up battle rifle (there are several FN-FAL types that folks have built up into larger calibers, like 338/358), or even just a battle rifle loaded with premium hunting rounds (barnes solid-X copper slugs, etc).